diff options
| author | Luigi Semenzato | 2019-07-12 06:00:10 +0200 |
|---|---|---|
| committer | Linus Torvalds | 2019-07-12 20:05:47 +0200 |
| commit | ee2ad71b0756e995fa4f6d922463e9bccd71b198 (patch) | |
| tree | 0ca5415368b95cbe6890d915a98fc83c9e1eee3e /Documentation/ABI | |
| parent | mm: use down_read_killable for locking mmap_sem in access_remote_vm (diff) | |
| download | kernel-qcow2-linux-ee2ad71b0756e995fa4f6d922463e9bccd71b198.tar.gz kernel-qcow2-linux-ee2ad71b0756e995fa4f6d922463e9bccd71b198.tar.xz kernel-qcow2-linux-ee2ad71b0756e995fa4f6d922463e9bccd71b198.zip | |
mm: smaps: split PSS into components
Report separate components (anon, file, and shmem) for PSS in
smaps_rollup.
This helps understand and tune the memory manager behavior in consumer
devices, particularly mobile devices. Many of them (e.g. chromebooks and
Android-based devices) use zram for anon memory, and perform disk reads
for discarded file pages. The difference in latency is large (e.g.
reading a single page from SSD is 30 times slower than decompressing a
zram page on one popular device), thus it is useful to know how much of
the PSS is anon vs. file.
All the information is already present in /proc/pid/smaps, but much more
expensive to obtain because of the large size of that procfs entry.
This patch also removes a small code duplication in smaps_account, which
would have gotten worse otherwise.
Also updated Documentation/filesystems/proc.txt (the smaps section was a
bit stale, and I added a smaps_rollup section) and
Documentation/ABI/testing/procfs-smaps_rollup.
[semenzato@chromium.org: v5]
Link: http://lkml.kernel.org/r/20190626234333.44608-1-semenzato@chromium.org
Link: http://lkml.kernel.org/r/20190626180429.174569-1-semenzato@chromium.org
Signed-off-by: Luigi Semenzato <semenzato@chromium.org>
Acked-by: Yu Zhao <yuzhao@chromium.org>
Cc: Sonny Rao <sonnyrao@chromium.org>
Cc: Yu Zhao <yuzhao@chromium.org>
Cc: Brian Geffon <bgeffon@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation/ABI')
| -rw-r--r-- | Documentation/ABI/testing/procfs-smaps_rollup | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/Documentation/ABI/testing/procfs-smaps_rollup b/Documentation/ABI/testing/procfs-smaps_rollup index 0a54ed0d63c9..274df44d8b1b 100644 --- a/Documentation/ABI/testing/procfs-smaps_rollup +++ b/Documentation/ABI/testing/procfs-smaps_rollup @@ -3,18 +3,28 @@ Date: August 2017 Contact: Daniel Colascione <dancol@google.com> Description: This file provides pre-summed memory information for a - process. The format is identical to /proc/pid/smaps, + process. The format is almost identical to /proc/pid/smaps, except instead of an entry for each VMA in a process, smaps_rollup has a single entry (tagged "[rollup]") for which each field is the sum of the corresponding fields from all the maps in /proc/pid/smaps. - For more details, see the procfs man page. + Additionally, the fields Pss_Anon, Pss_File and Pss_Shmem + are not present in /proc/pid/smaps. These fields represent + the sum of the Pss field of each type (anon, file, shmem). + For more details, see Documentation/filesystems/proc.txt + and the procfs man page. Typical output looks like this: 00100000-ff709000 ---p 00000000 00:00 0 [rollup] + Size: 1192 kB + KernelPageSize: 4 kB + MMUPageSize: 4 kB Rss: 884 kB Pss: 385 kB + Pss_Anon: 301 kB + Pss_File: 80 kB + Pss_Shmem: 4 kB Shared_Clean: 696 kB Shared_Dirty: 0 kB Private_Clean: 120 kB |